# Introduction: The 13th Questions about Sound System

Q1:What is sound?

Sound is a form of energy which can be transferred to other forms of energy.

Q2:How the sound generated?
The sound generated by pressing on the air molecules getting it vibrating and moving in a pattern called sound wave.

For Example when you clap your hands, you press on the air molecules getting it vibrating and moving as sound wave to your ears hence you hear the clap sound.

Q3:What range can the sound wave propagated?
As we said, sound is form of energy so; the sound wave will continue propagation to a distance from the sound source in which it will looses its energy.

Q4:Can I hear any sound around?
Yes, you can but you must be in the range of this sound.

Q5:Why I hear loud sounds and sometimes low ones?
This is because of the vibration speed (propagation speed) for this sound wave whenever sound wave is being faster it will be louder.

For Example when you throw a stone in water, if you throw it with fast movement (need more energy) the water waves will be faster than if you do the same with slow movement (less energy).

Q6:How I can transmit the sound to far distance?
It is based on sound signals' energy value but we can by using some devices amplify this energy value causing it to propagate for far distances.

Q7:Can the sound waves propagate in water or other medium?
Yes, it can and it will be faster than in the air medium because that the water molecules are more bonded and near each other than that of air.

Q8:Can I hear sound in space?
No, you can't because there is no media (like air or water) which can transmit sound waves.

Q9:How the sound wave be represented?
It represented as a sine wave while it was in nature a longitude one moving in the direction of energy or pressure movement.

Q10:What sound waves can be audible?
When the speed variations in pressure occur between 20 and 2000 times per second (i.e. at frequency between 20HZ and 20KHZ) sound can be audible.

Q11:What are the sound wave properties?
• Frequency
• Wavelength
• Wave number
• Amplitude
• Intensity
• Speed
• Direction

Note: please see these terms definitions under the topic of Dictionary of sound system.

Q12:How can the sound be measured?
By using a device called sound level meter, the famous measurement unit of sound is the decibel (dB)
We can also use an oscilloscope to view characteristic of sound waves on its screen.

Q13:Finally, what is the speed value of sound in air?
It is 1,120 feet (340 meter) per second

In the next topic, I will explain the sound system description.